Seaside alder named ‘September Sun’

ABSTRACT

A new variety of  Alnus maritima  subsp.  oklahomensis  plant named ‘September Sun’ that is characterized by fast vertical growth of ≈89 cm (35 inches) per year over the first two years after establishment in the landscape and fast canopy volume growth of ≈4.8 m3 (170 cubic feet) during the second year after establishment. The strobili (infructescences) of ‘September Sun’ are small (17 mm long and 10.2 mm wide) and slender (length:width ratio=1.7) compared to the average for  oklahomensis.  In combination, these traits set ‘September Sun’ apart from all other existing varieties of  Alnus maritima  subsp.  oklahomensis  known to the inventors.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Development of this technology was federally funded under the following USDA/CSREES grants: 98-CRHF-0-6019; 99-CRHF-0-6019; 00-CRHF-0-6019; 2001-31100-06019; 2002-31100-06019; 2003-31100-06019.

Botanical designation:

Alnus maritima, subspecies oklahomensis.

Variety denomination: ‘September Sun.’

BACKGROUND

The present invention relates to the field of ornamental plants.

The present invention is a new and distinct variety of Alnus maritima, commonly known as “Seaside Alder,” that is grown and utilized as an ornamental landscape tree or shrub. The new variety is known botanically as Alnus maritima subsp. oklahomensis and will be referred to hereinafter by the variety name, ‘September Sun.’

Plants of Alnus maritime are native to North America, and plants of subspecies oklahomensis specifically are native only to Oklahoma. The species is valued ornamentally for its dark green foliage, its bright-yellow, pendulous catkins that bloom in autumn, and its healthy appearance under conditions known to be stressful for other woody taxa. Subspecies oklahomensis is the most distinct of the three subspecies of Alnus maritima and represents the best of the species' ornamental and physiological traits. Efforts to develop superior cultivated varieties of subsp. oklahomensis began only recently in 1998.

Germplasm for ‘September Sun’ was obtained as seed from an open-pollinated parent growing naturally near Tishomingo, Okla. The inventors selected ‘September Sun’ as a single whole plant from a large seedling trial at Ames, Iowa in 2000. The inventors selected and confirmed ‘September Sun’ to be unique within subsp. oklahomensis for its faster growth, denser foliage, more symmetrical growth habit, and smaller, more slender infructescences shown in field trials with over 1000 plants. The vertical growth rate of ‘September Sun’ was shown to be approximately 73% greater than the mean for other genotypes of subsp. oklahomensis, and it volume growth rate greater than the mean. The strobili (cone-line infructescences) of ‘September Sun’ are 11% shorter and 18% smaller in diameter than the mean for other genotypes of subsp. oklahomensis.

The inventors carried out the first asexual propagation of ‘September Sun’ in 2000 at Ames, Iowa by rooting softwood cuttings of the original single plant. All of the resulting plants exhibited the typical characteristics of ‘September Sun’. The inventors determined from successive generations of asexual propagation that the new variety ‘September Sun’ is stable and propagates true to type.

‘September Sun’ is registered with the International Cultivar Registration Authority, Brooklyn Botanical Garden (international authority for unassigned woody ornamentals), 1000 Washington Avenue, Brooklyn, N.Y. 11225-1099.

BRIEF SUMMARY

The following traits have been consistently observed, and represent the characteristisc of the new variety ‘September Sun.’ These traits in combination distinguish this variety from naturally occurring genotypes of subspecies oklahomensis and from other commercially available varieties known to the inventors. ‘September Sun’ has not been tested under all possible conditions, and phenotypic differences may be observed with variation in environmental, climatic and cultural conditions.

-   -   1. ‘September Sun’ is fast growing, with vertical growth of ≈89         cm (35 inches) per year over the first two years after         establishment in the landscape (73% faster growth than the         average genotype of subsp. oklahomensis). Canopy volume growth         is extremely fast with an increase of ≈4.8 m³ (170 cubic feet)         during the second year after establishment (234% faster growth         than the average genotype of subsp. oklahomensis).     -   2. The strobili (infructescences) of ‘September Sun’ are small         and slender. They measure ≈17 mm long and 10.2 mm wide, with a         length to width ratio of 1.7 (11% shorter and 18% smaller in         diameter than the average).     -   3. ‘September Sun’ is densely foliated (relative to the subsp.);         with a foliage density rating of 10 (1=least dense; 10 is most         dense); whereas the average density rating for other genotypes         of subsp. oklahomensis is 7.     -   4. ‘September Sun’ has a consistently symmetrical growth habit         with a symmetry rating of 10 (1=least symmetry, 10=most         symmetry) whereas the average symmetry rating for other         genotypes of subsp. oklahomensis is 8.

SUMMARY OF THE INVENTION

The present invention is summarized in a new variety of ornamental plant of the species Alnus maritima subsp. oklahomensis. The new variety is named ‘September Sun’ and is characterized by rapid growth and fall foliage color.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of the habit of the typical seaside alder ‘September Sun’ in an image showing several plants of the variety with similar habits.

FIG. 2 is an illustration of the fall foliage of the seaside alder ‘September Sun’ in an image showing several plants of the variety with similar fall foliage.

FIG. 3 is an enlarged view of the foliage and catkins of the seaside alder ‘September Sun.’

BOTANICAL DESCRIPTION OF THE PLANT

The following is a description of the new variety, ‘September Sun’. Data were collected from plants grown in outdoor conditions in field trials at Ames, Iowa, and plants were approximately three years old at the time of data collection.

Detailed descriptions and a key for the subspecies of Alnus maritima are provided in Schrader and Graves (2002).

-   Botanical classification: Alnus martima (Marsh.) Muhl. ex Nutt.     subsp. oklahomensis Schrader & Graves ‘September Sun’. -   Commercial classification: Shrub or small tree for planting in the     landscape. -   Common names: Seaside Alder, Oklahoma Alder. -   Use: Ornamental or windbreak plant for use in hedging or as a     landscape specimen. -   Parentage: Open-pollinated seed parent Alnus maritima subsp.     oklahomensis growing on the bank of the Blue River near Tishomingo,     Okla. (lat. 34°19′38″N., long. 96°35′25″W.). -   Plant description:     -   -   Bloom period.—Early autumn.         -   Plant habit.—Upright large shrub with a broad-rounded crown.         -   Height.—2.4 m (7.9 ft.) after three years; 7 m (23 ft.) at             full size if unpruned.         -   Width.—1.8 m (5.9 ft.) after three years; 6 m (20 ft.) at             full size if unpruned.         -   Hardiness.—USDA Zones 4 through 9.         -   Propagation.—By softwood cuttings. Rooting is optimized with             rooting compound.         -   Time to develop roots.—6 to 9 weeks under intermittent mist.         -   Crop time.—From 6 to 8 months are needed to produce a plant             large enough for landscape installation. Plants flower             during second season in the landscape.         -   Pest and disease issues.—None of note.         -   Cultural requirements.—‘September Sun’ is tolerant of             partial shade and a wide range of soil types and conditions,             but grows best in full sun and wet soils. -   Stem:     -   -   Shape.—Cylindrical.         -   Color.—Young stems light green becoming brown. Bark is brown             when new, then turning light gray and becoming darker gray             with age.         -   Surface.—Bark smooth, becoming slightly rough with age, with             lenticels near the base.         -   Branching habit.—Strong axillary branching. Single trunk             first season, multiple trunks thereafter. -   Foliage:     -   -   Type.—Deciduous.         -   Shape.—Blade ovate, elliptic or narrowly elliptic. Apex             acute, sometimes acuminate.         -   Size.—Blade 7.5 cm to 9 cm long, 3 cm to 4 wide. Petiole 13             mm to 21 mm long, 0.75 mm to 1.5 mm in diameter.         -   Margin.—Serrate with single ascending teeth.         -   Arrangement.—Alternate. -   Inflorescence:     -   -   Staminate.—1 to 6 catkins in racemose clusters at ends of             current year's twigs. At anthesis, yellow and pendent, 2 cm             to 8 cm long, 5 mm to 7 mm in diameter, on peduncles 4 mm to             18 mm long, 0.5 mm to 1 mm in diameter.         -   Pistillate.—Solitary in axils of the first to fourth leaves             from apex, on twigs bearing staminate catkins. At anthesis,             erect, ovate to elliptic, 3 mm to 4.5 mm long, 1.5 mm to 2.5             mm in diameter, on peduncles 5 mm to 7 mm long, 1 mm to 2 mm             in diameter.         -   Anthesis.—Mid-August to mid-September. -   Infructescence:     -   -   Type.—Cone-like strobili.         -   Shape.—Ovoid or ellipsoid; length to width ratio of 1.7.         -   Size.—≈17 mm long and 10.2 mm wide, on peduncles 5 mm to 10             mm long, 1 mm to 2 mm in diameter.         -   Maturation.—One year after pollination. Fruit drop December             to March. Strobili persist on plants 1 to 2 years after             fruit drop.         -   Fruits.—Light to dark brown, elliptic, 1 mm to 3 mm long, 1             to 2 mm wide, with wings narrow to absent and two persistent             styles 0.4 mm to 0.8 mm long.

A herbarium specimen of ‘September Sun’ [May 18, 2003, J. Schrader 123 (ISC)] is on deposit at the Ada Hayden Herbarium (ISC), Iowa State University, Ames, Iowa 50011. A photograph and herbarium specimen of ‘September Sun’ have been deposited at the Brooklyn Botanical Garden (international registration authority for unassigned woody ornamentals), 1000 Washington Avenue, Brooklyn, N.Y. 11225-1099.

The cultivar ‘September Sun’ differs from other known genotypes of its species as it is the fastest growing, most densely foliated, and most symmetrically shaped individual plants that have been observed in field trials including over one thousand plants of the subspecies conducted to date. During a trial that was conducted over three growing seasons at a site in Ames, Iowa, ‘September Sun’ grew larger and developed a more symmetrically canopy shape than did other seedlings of A. maritima subsp. oklahomensis in that trial, including half-siblings of the original ‘September Sun’ plant. Shown below in Table 1 is an illustration of the trunk and size characteristics of four representative plants of this subspecies grown in this trial.

TABLE 1 Genotype Trunk Canopy Canopy (m³) diam^(z) (mm) height^(y) (cm) volume^(x) ‘September Sun’ 30.8 a^(w) 238.9 a 6.17 a ‘Blue River #6’ (unpatented) 23.0 ab 166.3 b 2.35 b ‘Pennington #5’ (unpatented) 24.0 ab 155.1 b 1.72 bc ‘Pennington #6’ (unpatented) 19.9 b 142.1 b 1.16 c ^(z)Diameter of the largest trunk at 10 cm above the soil surface. ^(y)Distance from the soil surface to the apex of the tallest shoot. ^(x)Canopy volume was calculated by multiplying the shoot height by the horizontal canopy area (area of an ellipse calculated from the north-south and east-west canopy diameter measurements). ^(w)Means within each column followed by the same letter are not significantly different at P ≦ 0.05 according Student's T-test. N = 1 for ‘September Sun’, N = 8 for ‘Blue River #6’ and ‘Pennington #5’, N = 10 for ‘Pennington #6’. Dunnett's test for comparing treatment groups against a control (Stevens, 1990) was used to confirm differences between ‘September Sun’ and the three half-sibling groups.

To facilitate the identification of the variety, the Macbeth-Munsell Disk Colorimeter was used to specifically identify colors of the important plant parts. The top side of the young leaf emerging from twigs is 5 GY 4/6. The lower side of the young leaf emerging from twigs is 5 GY 5/4. The top side of the mature leaf is 7.5 GY 2/4. The fall foliage is variegated, but the most predominant color is 7.5 Y 7/6. The Male inflorescence or flower cluster is 2.5 Y 7/6. The female inflorescence is 10 RP 4/12. The fully mature fruiting structure, or strobili, is 10 YR 2/1. 

1. A new and distinct variety of seaside alder plant named ‘September Sun,’ substantially as herein shown and described, characterized by fast growth, dense foliation, and symmetrically shaped individual plants that become mottled blends of orange, yellow and rich brown in autumnal conditions. 